# Rational Nonmonotonic Reasoning

**Carl M. Kadie**

Microsoft Research, Bldg 9S

Redmond 98052-6399, WA

**Author Email: ****carlk@microsoft.com**

### Abstract:

*Nonmonotonic reasoning is a pattern of reasoning that allows an agent to
make and retract (tentative) conclusions from inconclusive evidence. This paper
gives a possibleworlds interpretation of the nonmonotonic reasoning problem
based on standard decision theory and the emerging probability logic. The
system's central principle is that a tentative conclusion is a decision to make
a bet, not an assertion of fact. The system is rational, and as sound as the
proof theory of its underlying probability logic.*

Proceedings of the Fourth Workshop on Uncertainty in Artificial Intelligence, Minneapolis, August 1988. (postscript)